1)

[tex] \frac{5a + {b}^{5} }{8b} - \frac{5a - 7 {b}^{5} }{8b} = \frac{5a + {b}^{5} - 5a + 7 {b}^{5} }{8b} = \frac{8 {b}^{5} }{8b} = {b}^{4} [/tex]

2)

[tex] \frac{2x - 3y}{4xy} + \frac{11y - 2x}{4xy} = \frac{2x - 3y + 11y - 2x}{4xy} = \frac{8y}{4xy} = \frac{2}{x} [/tex]

3)

[tex] \frac{3x - {y}^{4} }{4 {y}^{5} } - \frac{ {y}^{4} + 3x}{4 {y}^{5} } = \frac{3x - {y}^{4} - {y}^{4} - 3x}{4 {y}^{5} } = \frac{ - 2 {y}^{4} }{4 {y}^{5} } = - \frac{1}{2y} [/tex]

4)

[tex] \frac{a - 2}{7a} + \frac{2a + 5}{7a} - \frac{3 - a}{7a} = \frac{a - 2 + 2a + 5 - 3 + a}{7a} = \frac{4a}{7a} = \frac{4}{7} [/tex]

5)

[tex] \frac{7y - 5}{11y} - \frac{10y - 9}{11y} + \frac{10 - 5y}{11y} = \frac{7y - 5 - 10y + 9 + 10 - 5y}{11y} = \frac{ - 8y + 14}{11y} [/tex]

6)

[tex] \frac{21a + 2b}{6a} + \frac{21a - 3b}{6a} - \frac{36a - b}{6a} = \frac{21a + 2b + 21a - 3b - 36a + b}{6a} = \frac{6a}{6a} = 1[/tex]